| 摘要 |
PURPOSE:To reduce manufacturing costs, by subjecting a steel bar after conclusion of finish rolling in hot rolling to temp. control and then by charging it into a heat-treatment furnace to apply normalizing so as to utilize the sensible heat of the steel bar as heat-treating temp. CONSTITUTION:A hot-finish-rolled steel bar by means of a rolling line 1 is fed to a cutter 2 and cut into the prescribed length, and then introduced into a heat treatment line. At this time, when the sensible heat of the steel bar is high, the steel bar is fed into a forced air cooling zone 3 to undergo force cooling down to a heat treatment-starting temp. Subsequently, this steel bar is fed to a heat-treatment furnace 4 to undergo prescribed heat treatment and then cooled at a regulated velocity for normalizing in a forced air cooling zone. In this way, the manufacturing time of the steel bar is shortened and fuel cost is economized.
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